Portable apparatus for the calcination of minerals



1967 A. BOCHARAN GARCIA 3,306,593

PORTABLE APPARATUS FOR THE CALCINATION OF MINERALS Filed Dec. 9, 1964 INVENTOR l ASCENSIN BOCHARAN GARCIA United States Patent Ofitice 3,306,593 Patented Feb. 28, 1967 3,306,593 PORTABLE APPARATUS FOR THE CALCINA- TIQN F MINERALS Ascensin Bocharan Garcia, Calle Toledo 43, Ciudad Real, Spain Filed Dec. 9, 1964, Ser. No. 417,181 Claims priority, application Spain, Dec. 17, 1963, 294,593; Apr. 22, 1964, 299,032 8 Claims. (Cl. 2631) The present invention concerns a portable apparatus for the calcination of minerals especially gypsum, plaster or lime, provided with a mechanical furnace preferably fed with liquid fuels, but also capable of using solid fuels such as coal or Wood.

According to the present invention a portable apparatus for the calcination of minerals, comprises a chassis or frame provided with wheels and supporting a calcination furnace, a chamber for pre-heating the mineral, a crushing mill and a storage container for the product obtained, characterised by the feature that the combustion cavity of the furnace is formed by a space between two groups of parallel and rotatable tubes within which the mineral is conveyed in the same direction as the combustion gases by a screw conveyor provided in each of the tubes, until passing through the ends of the tubes remote from the mouth of the furnace, the calcinated material then being collected for grinding by a conventional grinding mill and subsequent storage, hot gases and vapours from the tubes also being collected and mixed with hot gases from the combustion of the furnace and introduced into the preheating chamber in which further rotary tubes are also provided, each further tube having a screw conveyor for feeding the mineral, which is supplied to the apparatus through the end of these tubes remote from the mouth of the furnace and which issues pre-heated through the ends of said further tubes which in the region of the mouth of the furnace and from where the material drops into a chamber for charging the tubes of the furnace, which, by means of their screw conveyors, collect the preheated mineral to be duly calcinated.

The invention will now be described further by way of example, with reference to the accompanying drawings in which the single figure shows, schematically and partly cut away for clarity, an apparatus constructed in accordance with the invention.

The apparatus shown in the drawing comprises a base or chassis I mounted on wheels 2, on which chassis 1 there are mounted three bodies, a furnace, a pre-heating chamber 4 and a storage container 5.

The furnace is formed of a casing or housing 3 suitably covered with heat [insulating material, within which there is provided two groups of rotatable tubes 6 disposed parallel to each other and to the axis of the casing 3 of the furnace. Each group of said tubes 6 extends along one side of the furnace and together form a chamber within which combustion takes place by means of burners 7 of liquid or powdered fuels, or by means of solid fuels such as wood or coal which may be accommodated on a grating 8 disposed in the chamber between the groupsof tubes 6.

Each tube 6 contains a screw conveyor 9 which advances treated material in the direction of arrow 10, that is to say, away from the hottest zone of the furnace. The tubes 6 which have their ends received in circular apertures provided in end plates 11 of the furnace housing 3, gradually rotate as the screws 9 convey the material therethrough. The driving end of each screw 9 has a shaft extension which passes through a further plate 12 where each screw is provided on the outside of the plate 12 with a gear wheel 13, the gear wheels 13 of each group of tubes 6 and screws 9 being intermeshed and driven externally by a suitable gear motor 42. The gear wheels 13 are enclosed by a cover 14.

The plates 11 and 12 form a loading chamber 15 which can be separated into two separate chambers 15 and 15' when closed laterally. At the opposite end of the tubes 6 there is another similar chamber 16 into which the calcinated mineral is unloaded. Hot vapours, illustrated by arrow 18, and which emanate from the tubes 6, collect in tubes 19 together with gases illustrated by arrows 20 which are even hotter from the combustion.

These hot vapours and gases flow into the pre-heating chamber 4 where, after heating tubes 21, they are removed by an air suction mechanism 22, and thrown outside the apparatus.

The tubes 21 in the pre-heating chamber 4 are similar to those of the furnace by being rotatable and by having screw conveyors 24 which are rotatable by means of toothed wheels 23, the screws 24 compelling the mineral deposited in a hopper 25 to move in the direction of arrow 26, drop into a loading chamber 27 and then travel in the direction of arrow 28 whilst being heated by the vapours and gases fed through the tubing 19 to the preheating chamber 4. When the mineral, already heated, issues from the end of a tube 21, it falls in the direction of arrow 29 into the loading chamber 15 of the furnace, and similarly when it arrives at the end of tubes 6 it falls in the direction of arrow 17 to a conventional mill 30. By means of already known processes the ground material travels in the direction of arrow 31 until it drops into a receiving chamber 32 of a storage container 5 from where a screw conveyor 33 compels it to advance along a tube 37 and fall through one of a succession of small tubes 34 provided along the length of tube 37. The ground material travelling along tube 37 will fall through the first tube 34 until it becomes blocked by the rising level of stored material, after which the material advances further and discharges through a new opening in the di rection of the arrow 35 resulting in the complete filling of the storage container 5.

An aspirator (not shown) sucks cool air from outside and sends it in the direction indicated by the arrow 36 to cool the tube 37 through the interior of which the screw conveyor 33 feeds the caclinated and ground mineral which is still hot, this air flowing out at 38 into the atmosphere.

The mineral can be removed from the storage container 5 by means of tubes 39, each provided with a screw conveyor 40, the shafts of which terminate in a square, triangular or the like shape which fits into the end of a screw conveyor of another tube (not shown) which may be connected to tube 39 if so desired.

What I claim is:

1. An apparatus for the calcination of minerals comprising:

a calcination furnace including two groups of parallel and rotatable tubes forming a space defining a combustion chamber having a mouth at one end, conveyor means in each tube for pushing the material through the tubes in the same direction as the combustion gases and through the ends of the tubes remote from said mouth;

a preheater chamber including a plurality of rotatable tubes, conveyor means in each tube for feeding mineral in a direction toward the mouth of said furnace;

means for supplying mineral to said last mentioned tubes at the ends thereof remote from the mouth of the furnace;

means for conveying mineral discharged from the last mentioned tubes to the first mentioned tubes; andv means for directing hot gases from the furnace over said last mentioned tubes.

2. An apparatus as set forth in claim 1 wherein said last mentioned means includes means for collecting and mixing hot gases and vapours from the first mentioned tubes and mixing said hot gases and vapours with the hot gases and vapours from said furnace for directing such mixture over said last mentioned tubes.

3. An apparatus as set forth in claim 1 and including means for collecting and grinding mineral discharged from the first mentioned tubes.

4. An apparatus as claimed in claim 3 wherein the ends of the rotatable tubes open into charging and discharging chambers and wherein baffie means are provided for separating said charging and discharging chambers into two separate members so that two different minerals may be treated separately through respective sets of said tubes.

5. An apparatus as claimed in claim 1 wherein the ends of said rotatable tubes open into discharge chambers, the gases produced in the minerals being collected from the discharge chamber of the furnace tubes and mixed with gases from the combustion of the furnace, said tubes being provided with regulating members which connect the end of the furnace remote from its mouth, the discharge chamber of the furnace tube and the end of the preheating chamber, and an air suction mechanism located at the end of the preheating chamber near its discharge chamber for circulating the hot gases and vapours,

6. An apparatus as claimed in claim 1 in which the furnace is provided with burners for liquid fuels and also with grates suitable for burning solid fuels.

7. An apparatus as claimed in claim 1 including:

a crushing mill;

means connecting the discharge of said rotatable tubes to said crushing mill for crushing of said mineral;

hopper means for receiving mineral crushed by said crushing mill, said hopper means including a fixed tube having uniformly spaced apertures along its length;

a screw conveyor in said fixed tube;

a plurality of radially disposed tubes, each extending from a respective one of said apertures;

a storage chamber below said fixed tube, said radially disposed tubes providing for discharge of the mineral into said storage chamber;

an additional tube coaxial with said fixed tube; and

means for passing cooling air from the outside between said fixed tube and said additional tube.

8. An apparatus as claimed in claim 7 in which the storage chamber for the product obtained is provided with a discharge system, said discharge system consisting of a series of tubes forming the outlet of the chamber, a screw conveyor within each of said tubes, one end of each conveyor having a shaft adapted to be received in a correspondingly shaped recess of an additional tube such that a plurality of such tubes and screw conveyors may be connected end to end.

References (Cited by the Examiner UNITED STATES PATENTS 233,568 10/1880 Southan 263-37 1,066,067 7/1913 Vorraber 26334 DONLEY I. STOCKING, Primary Examiner.

FREDERICK L. MATTESON, IR., Examiner.

J. I. CAMBY, Assistant Examiner. 

1. AN APPARATUS FOR THE CALCINATION OF MINERALS COMPRISING: A CALCINATION FURNACE INCLUDING TWO GROUPS OF PARALLEL AND ROTATABLE TUBES FORMING A SPACE DEFINING A COMBUSTION CHAMBER HAVING A MOUTH AT ONE END, CONVEYOR MEANS IN EACH TUBE FOR PUSHING THE MATERIAL THROUGH THE TUBES IN THE SAME DIRECTION AS THE COMBUSTION GASES AND THROUGH THE ENDS OF THE TUBES REMOTE FROM SAID MOUTH; A PREHEATER CHAMBER INCLUDING A PLURALITY OF ROTATABLE TUBES, CONVEYOR MEANS IN EACH TUBE FOR FEEDING MINERAL IN A DIRECTION TOWARD THE MOUTH OF SAID FURNACE; MEANS FOR SUPPLYING MINERAL TO SAID LAST MENTIONED TUBES AT THE ENDS THEREOF REMOTE FROM THE MOUTH OF THE FURNACE; MEANS FOR CONVEYING MINERAL DISCHARGED FROM THE LAST MENTIONED TUBES TO THE FIRST MENTIONED TUBES; AND MEANS FOR DIRECTING HOT GASES FROM THE FURNACE OVER SAID LAST MENTIONED TUBES. 